<?php
class Mysql{
    private static $_instance = NULL;  //数据库实例
    private $db_host;   //数据库主机
    private $db_user;   //数据库用户名
    private $db_pwd;   //数据库用户名密码
    private $db_database;  //数据库名
    protected $db_prefix;  //数据表前缀
    private $coding;   //数据库编码，GBK,UTF8
    private $conn;  //数据表前缀
    private $result;   //执行query命令的结果资源标识
    private $sql;    //sql执行语句
    private $row;    //返回的条目数
    private $bulletin = true; //是否开启错误记录
    private $show_error = true; //测试阶段，显示所有错误,具有安全隐患,默认关闭
    private $is_error = false; //发现错误是否立即终止,默认true,建议不启用

    /* 构造函数关闭前门，禁止new实例化 */

    private function __construct() {
        
    }

    //单件模式调用方法
    public static function getInstance() {
        //if (!self::$_instance instanceof self){
        if (self::$_instance == NULL) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }

    /* 参数引入 */

    public function setOptions($db_host, $db_user, $db_pwd, $db_database, $coding, $db_prefix) {
        $this->db_host = $db_host;
        $this->db_user = $db_user;
        $this->db_pwd = $db_pwd;
        $this->db_database = $db_database;
        $this->coding = $coding;
        $this->db_prefix = $db_prefix;
        $this->connect();
    }

    //过滤表前缀.由table.构成
    public function filterPrefix($string) {
        $new_string = str_replace('table.', $this->db_prefix, $string);
        return $new_string;
    }

    /* 数据库连接 */

    public function connect() {
        if ($this->conn == "pconn") {
            //永久链接
            $this->conn = mysql_pconnect($this->db_host, $this->db_user, $this->db_pwd);
        } else {
            //即使链接
            $this->conn = mysql_connect($this->db_host, $this->db_user, $this->db_pwd);
        }

        if (!mysql_select_db($this->db_database, $this->conn)) {
            if ($this->show_error) {
                $this->show_error("数据库不可用：", $this->db_database);
            }
            exit();
        }
        mysql_query("SET NAMES $this->coding");
    }

    /* 数据库执行语句，可执行查询添加修改删除等任何sql语句 */

    public function query($sql) {
        if ($sql == "") {
            $this->show_error("SQL语句错误：", "SQL查询语句为空");
        }
        $this->sql = $sql;

        $result = mysql_query($this->sql, $this->conn);

        if (!$result) {
            //调试中使用，sql语句出错时会自动打印出来
            if ($this->show_error) {
                $this->show_error("错误SQL语句：", $this->sql);
            }
        } else {
            $this->result = $result;
        }
        return $this->result;
    }

    /* 创建添加新的数据库 */

    public function create_database($database_name) {
        $database = $database_name;
        $sqlDatabase = 'create database ' . $database;
        $this->query($sqlDatabase);
    }

    /* 查询服务器所有数据库 */

    //将系统数据库与用户数据库分开，更直观的显示？
    public function show_databases() {
        $this->query("show databases");
        echo "现有数据库：" . $amount = $this->db_num_rows();
        echo "<br />";
        $i = 1;
        while ($row = $this->fetch_array()) {
            echo "$i $row[Database]";
            echo "<br />";
            $i++;
        }
    }

    //以数组形式返回主机中所有数据库名
    public function databases() {
        $rsPtr = mysql_list_dbs($this->conn);
        $i = 0;
        $cnt = mysql_num_rows($rsPtr);
        while ($i < $cnt) {
            $rs[] = mysql_db_name($rsPtr, $i);
            $i++;
        }
        return $rs;
    }

    /* 查询数据库下所有的表 */

    public function show_tables($database_name) {
        $this->query("show tables");
        echo "现有数据表：" . $amount = $this->db_num_rows();
        echo "<br />";
        $i = 1;
        while ($row = $this->fetch_array()) {
            $columnName = "Tables_in_" . $database_name;
            echo "$i $row[$columnName]";
            echo "<br />";
            $i++;
        }
    }

    /**
      mysql_fetch_row()    array  $row[0],$row[1],$row[2]
      mysql_fetch_array()  array  $row[0] 或 $row[id]
      mysql_fetch_assoc()  array  用$row->content 字段大小写敏感
      mysql_fetch_object() object 用$row[id],$row[content] 字段大小写敏感
     * */
    /* 取得结果数据 */
    public function mysql_result_li($str) {
        return mysql_result($str);
    }

    /* 取得记录集,获取数组-索引和关联,使用$row['content'] */

    public function fetch_array() {
        return mysql_fetch_array($this->result);
    }

    //获取关联数组,使用$row['字段名']
    public function fetch_assoc() {
        return mysql_fetch_assoc($this->result);
    }

    //获取数字索引数组,使用$row[0],$row[1],$row[2]
    public function fetch_row() {
        return mysql_fetch_row($this->result);
    }

    //获取对象数组,使用$row->content
    public function fetch_Object() {
        return mysql_fetch_object($this->result);
    }

    //简化查询select
    public function findall($table) {
        $this->query("SELECT * FROM $table");
    }

    //简化查询select
    public function select($table, $columnName = "*", $condition = '', $debug = '') {
        $condition = $condition ? 'WHERE ' . $condition : NULL;
        if ($debug) {
            echo "SELECT $columnName FROM $table $condition";
        } else {
            $this->query("SELECT $columnName FROM $table $condition");
        }
    }

    //简化删除del
    public function delete($table, $condition, $url = '') {
        if ($this->query("DELETE FROM $table WHERE $condition")) {
            if (!empty($url))
                massage($url, '删除成功！');
        }
    }

    //简化插入insert
    public function insert($table, $columnName, $value, $url = '', $plus = '') {
        if ($this->query("INSERT INTO $table ($columnName) VALUES ($value) $plus")) {
            if (!empty($url))
                massage($url, '添加成功！');
        }
    }

    //简化插入replace
    public function replace($table, $columnName, $value, $url = '') {
        if ($this->query("REPLACE INTO $table ($columnName) VALUES ($value)")) {
            if (!empty($url))
                massage($url, '更新成功！');
        }
    }

    //简化修改update
    public function update($table, $mod_content, $condition, $url = '') {
        if ($this->query("UPDATE $table SET $mod_content WHERE $condition")) {
            if (!empty($url))
                massage($url);
        }
    }

    /* 取得上一步 INSERT 操作产生的 ID */

    public function insert_id() {
        return mysql_insert_id();
    }

    //指向确定的一条数据记录
    public function db_data_seek($id) {
        if ($id > 0) {
            $id = $id - 1;
        }
        if (!@ mysql_data_seek($this->result, $id)) {
            $this->show_error("SQL语句有误：", "指定的数据为空");
        }
        return $this->result;
    }

    //根据select查询结果计算结果集条数
    public function db_num_rows() {
        if ($this->result == null) {
            if ($this->show_error) {
                $this->show_error("SQL语句错误", "暂时为空，没有任何内容！");
            }
        } else {
            return mysql_num_rows($this->result);
        }
    }

    // 根据insert,update,delete执行结果取得影响行数
    public function db_affected_rows() {
        return mysql_affected_rows();
    }

    //输出显示sql语句
    public function show_error($message = "", $sql = "") {
        if (!$sql) {
            echo "<font color='red'>" . $message . "</font>";
            echo "<br />";
        } else {
            echo "<fieldset>";
            echo "<legend>错误信息提示:</legend><br />";
            echo "<div style='font-size:14px; clear:both; font-family:Verdana, Arial, Helvetica, sans-serif;'>";
            echo "<div style='height:20px; background:#000000; border:1px #000000 solid'>";
            echo "<font color='white'>错误号：12142</font>";
            echo "</div><br />";
            echo "错误原因：" . mysql_error() . "<br /><br />";
            echo "<div style='height:20px; background:#FF0000; border:1px #FF0000 solid'>";
            echo "<font color='white'>" . $message . "</font>";
            echo "</div>";
            echo "<font color='red'><pre>" . $sql . "</pre></font>";
            $ip = $this->getip();
        }
        echo "</div>";
        echo "</fieldset>";

        echo "<br />";
    }

    //释放结果集
    public function free() {
        @ mysql_free_result($this->result);
    }

    //数据库选择
    public function select_db($db_database) {
        return mysql_select_db($db_database);
    }

    //查询字段数量
    public function num_fields($table_name, $display = NULL) {
        $this->query("SELECT * FROM $table_name");
        $total = mysql_num_fields($this->result);
        if (!empty($display)) {
            for ($i = 0; $i < $total; $i++) {
                print_r(mysql_fetch_field($this->result, $i));
            }
        }
        return $total;
    }

    //获取表字段列表
    public function table_columns($table_name) {
        $this->query("desc $table_name");
        $row = 0;
        while ($single_columns = $this->fetch_row()) {
            $columns[$row++] = $single_columns[0];
        }
        return $columns;
    }

    //取得 MySQL 服务器信息
    public function mysql_server($num = '') {
        switch ($num) {
            case 1 :
                return mysql_get_server_info(); //MySQL 服务器信息
                break;

            case 2 :
                return mysql_get_host_info(); //取得 MySQL 主机信息
                break;

            case 3 :
                return mysql_get_client_info(); //取得 MySQL 客户端信息
                break;

            case 4 :
                return mysql_get_proto_info(); //取得 MySQL 协议信息
                break;

            default :
                return mysql_get_client_info(); //默认取得mysql版本信息
        }
    }

    //析构函数，自动关闭数据库,垃圾回收机制
    public function __destruct() {
        if (!empty($this->result)) {
            $this->free();
        }
        mysql_close($this->conn);
    }

}

?>